Method of treating flue products.



F. C. RYAN,

METHOD OF TREATING FLUE PRODUCTS, APPLICATION msn' FEB.24, 1914.

1, 132,320. Patented May 9, 1916.

. To all whom, z't-may concern:

. E srATE's PATENT orno FRANCIS 0. RYAN, or HAMMOND, INDIANA, AssIGNoaor ONE-HALF T0 UNITED STATES METALS'REFINING COMPANY, or CHROME, NEW JERSEY, A, CORPORA- TION OF NEW JERSEY.

METHOD or TREATING ELUE rnopuo'rs.

Specification of Letters Patent.

Patented May 9, 1916.

Application filed February 24,1914. Serial 110,820,650.

Be it known that I, FRANCIS G. RYAN, a citizen of the United States, residing at Hammond, in the county of Lake and'State of Indiana, have invented certain new and useful Improvements in Methods of Treating Flue Products; and I do hereby declare the following to be a full, clear, and exact description ofthe invention, such as will enable others skilled in the art to which it appertains to make and use thesame.

The invention relates to a' method of treating flue-products from roasting or smelting operations or other similar finely divided mineral bearing materials for the recovery of the metallic values contained therein.

The object of the invention is to provide a novel and improved method which will enable a. high percentage of the values contained in materials treated, and especially of the silver, copper and zinc, to be recovered more economically and with less danger to the operators than heretofore.

In the accompanying drawing the several steps of the preferred form of method are diagrammatically illustrated.

The invention will be further explained in connection with its application to the treatment of fume or flue-dust from ore treating furnaces. These finely divided materials which contain sulfates, o'jXids, and

metallic forms of the various metals and elements constituting the ores or furnace products treated, are first leached with hot water to extract all water soluble compounds such as'the-sulfates of zinc, arsenic and iron. The liquor containing these compounds is drawn off into a suitable tank,

heated'and blown with air to facilitate oxi-,

dation particularly of the iron. .After the water soluble compounds have been. removed, the residue is roasted with an excess of sulfuric acid which is preferably. added while the residue is still in a thoroughly moistened condition. The excess of sulfuric acid present insures the complete sulfation of the metals or metallic compounds excepting the silicia and gold, and aids in the solution of basic anhydrous salts of iron, cop per, zinc, etc., which may be present in the material which is being roasted, and also insures an acid working condition for the subsequent treatment of the material. The

roasted 'materials are then crushed (pref erably wet crushed) and boiled with a limited amount of water, Owing to the excess of sulfuric acid in the roast, the boiling is in an acid solution. This is important,

since it insures a more complete solution and consequent separation of the soluble compounds, and also prevents the formation and precipitation of insoluble basic sulfates which would otherwise occur. The solution which carries the sulfates of silver, copper, zinc, iron, 'etc., is separated from the insoluble compounds by filtration. The residue which contains the insoluble lead sulfate, the gold and. the silica, may then be":

treated by any suitable "metallurgical method for recovery of the lead and gold.

The sulfate liquor isthen treated in a pref.

cipitating tank, and at this stage in the process the liquor collected in the storage tank from the first leaching above described. 1s preferably added to the sulfate liquor... This is desirable since it collects the mate rials to be treated, and at the same timethe water from the storage tank decreases the" impurities is treated by accept ed metallurgical methods for the recovery of the zinc, silver and copper. The filtrate may also be treated for the recovery of any values contained therein.

While it is preferred to employ all the steps described in treating the materials from which the values are to be recovered, this is not essential to certain features of the invention, and it will be understood that certain steps of the complete. process may be employed with advantage even if one or more of the other steps are omitted. For instance, the leaching with water before roasting with excess of sulfate acid is desirable," althcugh not; essential, and in case be separately' treated, although f it is 'pre ferred' to add this liquorto the sulfate liquor in the precipitating tank,.a's above described I a a a Having explained the nature" andhobj'ect ofthe-invention', and specifically explained one manner in "which it may be practised, *Whatis claimed-isz a p 1. The method'of treating flue products or other finely divided mineral bearing ma terials consisting in 'roastin the materials with excess of sulfuricacidfiboiling the kroast in an acid solution, separating. the sea lutidn, precipitating basic salts by the addi tion of fsuificient) quantity of. a neutralizing agent to leave-the solutiqnslightly acid and separating the solution from the precipitate fonfurther treatmentte recoverthe me tallic valilestherein f I I 2. The methcd 'of'tt'reating flue 'prqducts' Y or" other finelyiv dividedmineral bearil'ig materials consisting in "leaching thematerials i with water, blowing: the resulting liquor a with air,'roasting,the. residue with excessiofsulfuric, acid, boiling the roasted materials in a limitedamcuntof water, separating fthe 'li' ucr' therefrem adding the solution lro nt e leaching to the liquor, 'precipii tatmg baslcsalt's, by addmg a neutraliking v patent in; be obtained 'terjlveeente each, bi addressing the "cemmieeloner et fltente, f

the values therein.

3, Themethod cf treating flue products] or other finely divided mineral bearing man teri'als consisting in, leaching the materials with Water, roastingithe' residue with excess 40 ;ment for zine.

agent, and separating thesolution froin the precipitate for further t of sulfuric acid, beiling rthe roastedmaterials, with a'limited 1 amount cf Water, 'sepw rating theliquor therefrom, "reducing the acidityicf theliquor to precipitate the basic a, sulfates of such e1 cments as iron, arsenic, P 45, holding, the zinc, copper, js'ilver, and cad --mium in" solution, and separatingkthe solution from the precipitate for" further treatment to recover the values therein. 4. The prccesslbf treating oxidized cmintreatment to recover i 35 eral bearingimmaterial comprising roasting the material' with a sufiicien't amount, of strcng sulfuric acid 'te insure an acid coindition of the, roasted material, adding "wa -ter to the roasted'material and boiling-um der Janfi acid condition; filtering, reducing the acidity hi the solution to a' slightlfiiacid condition to; precipitate impurities an l' l'sep arating the, solution for a subsequent treata a e f Witiie ss'es:

W.*';H. G0sTLIN, Jr., JOHN N. B IgMAN. 

